Hand-involved habits, most notably smoking, hair-twirling, nose-picking, nail-biting, skin-pulling and scratching, induce in the practicer a subconscious sense of pleasure, not only through some sense of relief, but also from the actual hand-article contact experienced during the behavior. For example, to a smoker the act of lighting, holding, and manipulating a cigarette is responsible for much of the perceived satisfaction and pleasure that the smoking habit brings to many smokers. These actions often become subconsciously associated with, and thus reinforce, the smoking behavior. It has been repeatedly demonstrated that, without adequate behavioral support methods (to address craving) smokers are unlikely to successfully (permanently) quit. Indeed, for smokers trying to break the habit, the psychological components of craving often greatly exceed the 1-2 weeks of symptoms associated with nicotine withdrawal.
Similarly, the act of touching the hair or nose with the hands, or of placing the fingers in the mouth becomes a source of perceived satisfaction or relief. When an individual attempts to quit the habit, craving lasts from weeks to many months or more. For the other hand-involved habits besides smoking there is no chemical dependency, only the tactile sensations are involved.
When studying the hand involvement in smoking, in particular, it is often observed that most smokers hold a cigarette either between the pointer and middle fingers at any one of various points between the proximal and distal interphalangeal joints (PIP, DIP); between the flexed, adducted thumb and the adjacent pointer finger ("pulp pinch"); or between the thumb, pointer and middle fingers ("three-point pinch"). Contact between the thumb and pointer and/or middle fingers is referred to herein as "opposition." Most smokers prefer to hold the cigarette in the dominant hand.
Established smoking cessation instruments or methods have involved nicotine replacement (gums, patches) and various behavioral methods to deter or reduce smoking behavior. The latter group has typically involved adaptations of a cigarette or cigarette substitute, or orchestrated cues to increase the interval between cigarettes.